Magnetic junk catcher



Feb. 14, 1956 H. D. DONHAM .MAGN ETIC JUNK CATCHER Filed May 24, 1952INVENTOR.

M W 0 0 u ATTOR/Vf/ United rates Patent MAGNETIC CATCHER Horace D.Donham, 0dessa,'Tex.

Application May 24, 1952, Serial No. 289,817

13 Claims. (Cl. 294*655) This invention relates to a well tool in thenature of a magnetic junk catcher, and more particularly to a magneticdevice in combination with a rotary shoe and adapted to be employed inwell drilling equipment to catch and retain metallic fragments in a wellbore when operated therein.

In the drilling of oil wells, and especially in fishing operationsemployed to remover lost equipment in such wells, it is customary toattach a rotary or annular toothed shoe to the lower end of a wash-overstring to provide a means for cutting a clearance between the fish andthe wall of the well bore, in order to facilitate .the loosening andremoval of the fish.

During the use of rotary shoes in carrying out fishing operations, it isfrequently desirable to maintain the cireulation of drilling mud or wellfluid, either downwardly through the string and upwardly in the boreabout the string, or in the reverse direction, to effect washingof thethe fish and the carrying disintegrated material upwardly for convenientremoval from the bore. Relatively small particles of disintegratedmaterial are readily .removed in this manner, while larger particles,and particularly large particles of metal, which are heavy, may becarried part way up by the circulating fluid, and then become lodged orsettled in some portion of the bore, where there may bean enlargment, orat some location where the velocity of the circulating fluid decreases,thus causing an accumulation of material likely to interfer with thefree flow of the circulating fluid, or to form an obstruction preventingproper operation of the equipment.

The present invention has for an important object the provision of amagnetic junk catcher for use in or in combination with well equipmentof the type referred to, whereby particles of metal which may find theirway into the rotary shoe may be retained therein, and may be removedwith the shoe and wash-over string on completion of the operation of theequipment.

Another object of the invention is to provide a magnetic junkcatcherwhich may be readily appliedtto well equipment of the type mentioned,without interferring with the operation or action of the rotary shoe, orwith the flow of circulating fluid through the equipment.

A further object of the invention is the provision of a magnetic junkcatcher which is adapted to be rotatably carried adjacent the rotaryshoe, and which will effectively retain particles of magnetic materialentering the .shoe with the circulating fluid.

A further object of the invention is to provide a magnetic junk catcherin the form of a compact unit -including a permanent magnet, and adaptedto be readily inserted in and removed from working position relative toamtary'shoe, said unit having or providing passageways for the flow ofcirculating fluid therethrough.

.-A still further object of the invention is the provision of a magneticjunk catcher, of simple design and :rugged construction, which is easilyreplaced for purposes of maintenance and repair, and which is capable ofwith- 2,734,767 Patented Feb. 14, 1956 standing the extreme conditionsof exposure and wear to which such a device is likely to be subjected.

The above and other important objects and advantages of the inventionwill best be understood from the follow ing detailed description,constituting a specification of the same, when considered in conjunctionwith the annexed drawings, wherein- Figure 1 is a vertical, central,sectional view, showing the magnetic catcher combined with a rotary shoeto form a part of the fishing equipment;

Figure 2 is a transverse cross-sectional view taken along the line 22 ofFigure 1, looking in the direction indicated by the arrows;

Figure 3 is a transverse cross-sectional view taken along the line 33 ofFigure 1, looking in the direction indicated by the arrows; and

Figure 4 is a .bottom end view, looking at the lower end of the deviceas illustrated in Figure 1.

Referring now to the drawings in greater detail, the numeral 10designates a tubular member or sleeve-like extension of a body 18, whichextension is of generally cylindrical formation and is provided at itslower end with an annular cutter 60 with downwardly directed teeth 12.The cutter serves as a means for cutting or disintegrating the formationor material in a 'well bore, or objects located therein, as well as foragitating material in the bore when the tool is rotated. .Above theteeth 12 the rotary cutter is provided with an internal annular upwardlyfacing shoulder 14. The tubular body extension is internally threaded,as indicated at 16, at its upper end, to receive the lower externallythreaded end 16 of the "body 18, which has at its upper end a pin 20 forconnection to the lower end of the usual wash-over string with which atool of this type is customarily employed. The threaded parts provide areleasable joint or connection between the body 18 and the tubularextension of the body.

The body18 is an elongate member and has a flow passage or boreextending longitudinally through it to handle fluid. The flow passagemay be enlarged by a counterbore 22 adjacent its lower end, for apurpose later to be made apparent.

In the normal use of equipment of the kind described above, the rotaryshoe or cutter rotates with the washoverstring to which the body isapplied to out and disintegrated the formation or material in the wellbore to form a clearance between the fish and the wall of the bore, orto distintegrate material which has become lodged in the well bore tofacilitate its removal, and a circulation of fluid is maintained duringthe operation of the cutter, downwardly through the wash-over string andbody and upwardly about the same, or in the reverse direction, to carrycit the particles of disintegrated material in order to remove the samefrom the well bore.

The magnetic junk catcher in accordance with the present invention islocated within the body extension 10, and is freely rotatable thereinbetween the internal shoulder 14 of the cutter and the lower end of thebody 18. The junkcatcher in the form shown comprises anonmagneticcylindrical body or case 24, preferably formed of bronze or othernon-magnetic material, and having an external diameter somewhat lessthan the internal diameter of the extension so the catcher can turn orrotate therein. "The catcher case '24 has its ends opposing and adjacentthe shoulder 14 and body 18 so the catcher is held between the internalshoulder 14 and the lower end of the coupling member 18. The case '24 isslightly shorter than the distance between the internal shoulder 14'andthe lower'end of the body 18, so that the catcher may rotate freelyrelative to the cutter.

The "case 24 is provided with suitable passageways 28 extendinglongitudinally therethrough and having communication with thecounterbore 22. The passageways 28 provide openings through whichcirculated fluid may pass, during the operation of the equipment. Theparticular catcher shown has, in addition to the non-magnetic case, aplurality of units of magnetic material that will be referred to aspermanent magnet units 32 carried in openings 30 provided in the body24, in suitably spaced relation. The magnet units are shown as elongatemembers, round in cross section, and the openings 30 provided to carrythem are bores extending longitudinally in the non-magnetic case fromone end to the other thereof. The upper end of the case is provided witha socket in the form of a counterbore 34 in which a plate or head 36 ispositioned. The head 36 is retained in the counterbore by suitablefastening means, such as the screws 38, or the like so that it ismaintained in contact with the upper ends of the several magnet units32.

At the lower end of the catcher the non-magnetic case 24 is providedwith recesses or openings 40 within which contact plates, such as thoseindicated at 42, are positioned. The plates 42 extend over the bores 30to engage and retain the permanent magnet units 32 within the case.Suitable fastening means, such as the screws 44 may be employed tosecure the plates to the case.

In the case illustrated there are four permanent magnet units 32 spacedapart in the non-magnetic case 24 and all connected together or relatedmagnetically at the upper end of the catcher by the common head 36. Atthe lower end of the catcher there are two spaced contact plates exposedat the lower end (see Fig. 4). One contact plate 42 engages and ismagnetically related to two of the permanent magnet units 32 forming amagnetic pole at the lower end of the catcher and the other contactplate 42 engages and is magnetically related to the other two permanentmagnet units 32 forming the other magnetic pole at the lower end of thecatcher. is, in effect, a permanent magnet assembly in or carried by anon-magnetic case and having spaced magnetic poles at the lower exposedend of the catcher and within the annular toothed cutter with which thecatcher is combined.

It will be apparent that the case 24 and magnet unit 32 with the headand contact plates related thereto may be readily assembled andpositioned in the body extension 10, and the body 18 may then be screwedinto the upper end of the extension to retain the junk catcher inoperating position. In the event that it becomes necessary to remove thecatcher, this may readily be accomplished by detaching the extensionfrom the body 18, whereupon no difliculty will be encountered inremoving the catcher, since it has a loose or working fit in the bodyextension. The magnet units 32 may be easily removed and replaced, whennecessary or desirable by removing the contact plates 42 from the bottomof the non-magnetic case, which can be accomplished withoutdisassembling the equipment.

In making use of the junk catcher, as described above, the same iscooperatively related to an annular cutter in the manner described andthe assembly is lowered into the well at the lower end of the wash-overstring, whereupon the cutter may be rotated, while maintaining a flow ofcirculating fluid through the tool in either direction. It will beapparent that the cutter may rotate freely relative to the case 24, andany loose fragments of magnetic metal entering the cutter will be caughtand held by magnetic action at magnetic contact plates which are exposedat the lower end of the catcher.

From the foregoing description and from the drawings, it will be seenthat the invention provides a magnetic junk catcher, which willcooperate advantageously with a rotary or annular cutter or similartool, wherever the same may be used, and which is easily replaceable forpurposes of maintenance and repair.

The construction The invention has been described in connection with aspecific embodiment of the same, but it will be understood that this isintended by way of illustration only, and that numerous changes can bemade in the construction and arrangement of the various parts withoutdeparting from the spirit of the invention, or the scope of the appendedclaims.

Having thus clearly shown and described the invention, what is claimedas new and desired to secure by Letters Patent is:

1. A well fishing tool including, a body with a fluid passage thereinand adapted to be carried by a tubular fluid carrying well string to berotated thereby, an annular toothed cutter mounted on the body toproject downwardly below the body and having an internal upwardly facingshoulder, and a permanent magnet junk catcher freely carried between theshoulder and the body and rotatable relative thereto, there being afluid passage in the fishing tool between the body and the lower end ofthe catcher where it opens within the cutter.

2. A well fishing tool including, a body with a fluid passage thereinand adapted to be carried by a tubular fluid carrying well string to berotated thereby, an annular toothed cutter mounted on the body toproject downwardly below the body and having an internal upwardly facingshoulder, and a permanent magnet junk catcher freely carried between theshoulder and the body and rotatable relative thereto, there being afluid passage in the fishing tool between the body and the lower end ofthe catcher where it opens within the cutter, the catcher including acase of non-magnetic and a unit of permanent magnet material within andcarried by the case.

3. A well fishing tool including, a body with a fluid passage thereinand adapted to be carried by a tubular fluid carrying well string to berotated thereby, an annular toothed cutter mounted on the body toproject downwardly below the body and having an internal upwardly facingshoulder, and a permanent magnet junk catcher freely carried between theshoulder and the body and rotatable relative thereto, there being afluid passage through the catcher between the body and the lower end ofthe catcher where it opens within the cutter.

4. A well fishing tool including, a body with a fluid passage thereinand adapted to be carried by a tubular fluid carrying well string to berotated thereby, an annular toothed cutter mounted on the body toproject downwardly below the body and having an internal upwardly facingshoulder, and a permanent magnet junk catcher freely carried between theshoulder and the body and r0 tatable relative thereto, there being afluid passage in the fishing tool between the body and the lower end ofthe catcher where it opens within the cutter, the catcher including acase of non-magnetic material engaged with the shoulder and the body andwith an opening therein, a permanent magnet in said opening and a plateat the lower end of the case exposed at the lower end of the catcher andwithin the cutter and engaging said magnet.

5. A well fishing tool including, a body with a fluid passage thereinand adapted to be carried by a tubular fluid carrying well string to berotated thereby, an annular toothed cutter mounted on the body toproject downwardly below the body and having an internal upwardly facingshoulder, and a permanent magnet junk catcher freely carried between theshoulder and the body and rotatable relative thereto, there being afluid passage in the fishing tool between the body and the lower end ofthe catcher where it opens within the cutter, the catcher including anelongate case of non-magnetic material, a pair of spaced permanentmagnets in the case, a head at the upper end of the case adjacent thebody engaging said magnets and a pair of exposed spaced plates at thelower end of, the body adjacent the case and one engaging one of saidmagnets and another engaging another of said magnets.

6. A well fishing tool including, an elongate body having a fluidpassage extending longitudinally therein and adapted to be carried by atubular fluid carrying string to be rotated thereby, a tubular bodyextension releasably connected thereto and depending therefrom, anannular toothed cutter carried by the extension at the lower end thereofand having an internal upwardly facing shoulder, and a permanent magnetjunk catcher freely rotatable in the extension and confined againstlongitudinal movement therein by the shoulder and body, there being afluid passage in the fishing tool between the upper end of the catcherand the lower end thereof and open at the upper end of the catcher tothe passage in the body and open at the lower end of the catcher withinthe cutter.

7. A well fishing tool including, an elongate body having a fluidpassage extending longitudinally therein and adapted to be carried by atubular fluid carrying string to be rotated thereby, a tubular bodyextension releasably connected thereto and depending therefrom, anannular toothed cutter carried by the extension at the lower end thereofand having an internal upwardly facing shoulder, and a permanent magnetjunk catcher freely rotatable in the extension and confined againstlongitudinal movement therein by the shoulder and body, there being afluid passage through the catcher between the upper end of the catcherand the lower end thereof and open at the lower end of the catcherwithin the cutter.

8. A well fishing tool including, an elongate body having a fluidpassage extending longitudinally therein and adapted to be carried by atubular fluid carrying string to be rotated thereby, a tubular bodyextension releasably connected thereto and depending therefrom, anannular toothed cutter carried by the extension at the lower end thereofand having aninternal upwardly facing shoulder, and a permanent magnetjunk catcher freely rotatable in the extension and confined againstlongitudinal movement therein by the shoulder and body, there being afluid passage in the fishing tool between the upper end of the catcherand the lower end thereof and open at the lower end of the catcherwithin the cutter, the catcher including permanent magnet andnon-magnetic elements extending lengthwise of the tool and establishingspaced magnetic poles at the lower end of the catcher and within thecutter.

9. A well fishing tool including, an elongate body having a fluidpassage extending longitudinally therein and adapted to be carried by atubular fluid carrying string to be rotated thereby, a tubular bodyextension releasably connected thereto and depending therefrom, anannular toothed cutter carried by the extension at the lower end thereofand having an internal upwardly facing shoulder, and a permanent magnetjunk catcher freely rotatable in the extension and confined againstlongitudinal move ment therein by the shoulder and body, there being afluid passage in the fishing tool between the upper end of the catcherand the lower end thereof and open at the lower end of the catcherwithin the cutter, the catcher including permanent magnet andnon-magnetic elements extending lengthwise of the tool and establishingspaced magnetic poles at the lower end of the catcher and within thecutter, the non-magnetic element of the catcher being at the exterior ofthe catcher adjacent the body, the extension and the shoulder.

10. A well fishing tool including, an elongate body having a fluidpassage extending longitudinally therein and adapted to be carried by atubular fluid carrying string to be rotated thereby, a tubular bodyextension releasably connected thereto and depending therefrom, anannular toothed cutter carried by the extension at the lower end thereofand having an internal upwardly facing shoulder, and a permanent magnetjunk catcher freely rotatable in the extension and confined againstlongitudinal movement therein by the shoulder and body, there being afluid passage in the catcher between the upper end of the catcher andthe lower end thereof and open at the lower end of the catcher withinthe cutter, the catcher including permanent magnet and non-magneticelements extending lengthwise'of the tool and establishing spacedmagnetic poles at the lower end of the catcher and within the cutter,the fluid passage open at the lower end of the catcher being in thenon-magnetic element of the catcher.

11. A junk catcher for use in a well tool and including, an elongatebody of non-magnetic material having an opening therein and a fluidpassage extending therethrough from one end to the other, a unit ofpermanent magnet material in the opening establishing a magnetic pole atone end of the catcher, and a contact plate at the said end of thecatcher in fixed position relative to the body and engaging said unit.

12. A junk catcher for use in a well tool and including, an elongatebody of non-magnetic material having a fluid passage extending throughit from one end to the other, spaced units of magnetic material in thebody extending longitudinally therein, a head at one end of the body andin contact with each of said units, and spaced contact plates at theother end of the body one in contact with one of said units and anotherin contact with another of said units.

13. A junk catcher for use in a Well tool and including, an elongatebody of non-magnetic material having spaced openings therein and a fluidpassage extending therethrough from one end to the other, spaced unitsof magnetic material in the openings and extending longitudinally of thebody, a head at one end of the body and in contact with each of saidunits, and spaced contact plates at the other end of the body one incontact with one of said units and another in contact with another ofsaid units.

References Cited in the file of this patent UNITED STATES PATENTS432,896 Porter July 22, 1890 2,431,361 Athy Nov. 25, 1947 2,451,231Manegold Oct. 12, 1948 2,522,294 Noble Sept. 12, 1950 2,539,435 KirbyIan. 30, 1951 2,556,849 Nolley et al June 12, 1951 2,657,752 Ballew etal. Nov. 3, 1953 2,668,077 Kirby Feb. 2, 1954

